until the main cats warmed up and were effective. As long as your car is properly warmed up you should do fine. Been about 5-6 years since we have had to pass emissions with any car pre-obd2 though in illinois. All I know is we had to get our older cars piping hot on the highway to get them to pass.
Then luckily they decided to be a broke state and stopped doing dyno roller tests and now just test if you have error codes with your obd2.